The present invention relates to automatic closing devices, such as, for example, automatic window lifters and roof closing installations in a motor vehicle, which are equipped with a pinch protection function and in which the control can receive a sleep mode.
Automatic closing devices usually have a closing element (window pane, sliding roof) which is driven electrically by electric motor. The electric motor is activated by a control unit which is coupled to an operating element, in order, as a function of actuation of the operating element, to activate the electric motor and to stipulate its direction of movement.
In closing devices on a motor vehicle, such as, for example, electric window lifters, electric sliding roofs and the like, it is necessary to ensure that no articles or body parts which may be damaged or injured are present during a closing action in which the closing element is moved in the direction of a stop edge (window frame, roof recess). In order to avoid such a situation, a control unit implements an algorithm which detects a pinching situation during a closing action of the closing element. When the pinching situation is detected, the closing action is interrupted or reversing is executed, in which the closing element at least briefly performs an opening movement.
The closing device is usually activated with the aid of the operating element, and, depending on the type of operation of the operating element, an automatic run may be activated, in which the closing element moves automatically in the opening direction or the closing direction, without the operating element having to remain actuated. In an automatic run mode, the automatic run can be activated for a specific time duration, for example when the operating element is actuated.
As a rule, to reduce the quiescent current in the control unit, what is known as a sleep mode is implemented, in which the control unit is essentially inoperative as long as the electric motor is switched off, no movement of the closing element in the opening or the closing direction is carried out and no further actuation of the operating element takes place. This serves for reducing the quiescent current consumption as far as possible, until the control unit is shifted into a normal operating mode by a wake-up signal.
Furthermore, particularly in the case of automatic window lifters, a function is implemented in which the pinch protection function is deactivated shortly before a complete closing position, in which the closing element bears against the stop edge, is reached. As a rule, the stop edge against which the closing element is moved is provided with a seal, so that, during a closing action, the resistance increases shortly before the closing element impinges on the stop edge. Deactivating the pinch protection function in this region ensures that a pinching situation is not wrongly detected when the closing element moves into the seal.
Whereas, in earlier systems, selflocking mechanisms were employed for moving the closing element, appreciable use is made of non-selflocking mechanisms for the purpose of improving efficiency. In order to block the closing element against manual movement of the closing element, suitable measures are usually provided which prevent the electric motor from being rotated manually. In spite of such measures for performing manual movement of the closing element, it may happen that the electric motor and the closing element can be moved a short distance before blocking commences.
If, during such an externally triggered movement of the closing element, the control unit is in the sleep mode, during which position detection for the closing element is inactive, maladjustment will therefore occur between position information stored in the control unit for the last-detected position of the closing element and the current position of the closing element. Particularly during a closing movement of the closing element, before which an externally triggered movement of the closing element has taken place in a preceding phase of a sleep mode, it may happen, in the case of such maladjustment, that the pinch protection function is deactivated too soon before the stop edge is reached and therefore there is no effective pinch protection active in this region. In other words, in such a situation, pinch protection is deactivated, even though the closing system has between the closing element and the stop edge an interspace which is sufficiently wide that articles or body parts may enter it and may be damaged or injured.